CAIRO (AP) — Dozens of people are battling hundreds of riot police for a second day outside a courthouse in Egypt's northern Mediterranean city of Alexandria where policemen are being tried for allegedly killing protesters during the nation's 2011 uprising.

Police fired tear gas at protesters who threw rocks at the security forces. A truck that transports riot police was set ablaze.

Violence broke out Sunday after the presiding judge resigned from the case without elaborating.

That means a new trial for the six senior police officers accused of using excessive force that led to the deaths of protesters during the unrest that ousted former Egyptian leader Hosni Mubarak.

Around 900 protesters died in the revolt that began Jan. 25, 2011, with some 300 killed in Alexandria alone.